1. Field of the Invention
The present invention relates to a TIG welding method and apparatus. More specifically, it relates to a TIG welding method and apparatus which cause an arc discharge between a workpiece and an electrode of a welding torch to cause the generation of a weld arc, use permanent magnets to cause the generation of a magnetic field around the weld arc, and make electromagnetic force which is generated due to electromagnetic interaction of the magnetic field and current act on a weld pool of the workpiece in welding.
2. Description of the Related Art
As a TIG welding method and apparatus which cause an arc discharge between a workpiece and an electrode of a welding torch to cause the generation of a weld arc, use permanent magnets to cause the generation of a magnetic field around the weld arc, and make electromagnetic force which is generated due to electromagnetic interaction of the magnetic field and current act on a weld pool of the workpiece in welding, there are the method etc. which are described in Japanese Patent Publication (A) No. 2008-105056.
See Japanese Patent Publication (A) No. 2008-105056 for the related art.
However, when using the welding method of Japanese Patent Publication (A) No. 2008-105056, it is not possible to obtain a higher aspect ratio weld zone cross-sectional shape. The “aspect ratio” means the ratio of the melt depth H and average melt width W. Further, as shown in Example 2 of Japanese Patent Publication (A) No. 2008-105056 (FIG. 2), when arranging permanent magnets around the electrode of a welding torch, there is the inconvenience that sometimes the heat radiated from the weld arc causes the permanent magnets to overheat.